The life course is characterized by normative transitions that are often associated with major life events. Much existing research suggests that people readily adapt to these events. Based on this evidence, some researchers have argued that people have genetically determined emotional set-points to which they inevitably return after a period of adaptation. If so, that would mean that people who experience extreme emotional reactions to major life changes will inevitably return to their baseline levels of emotions after some period of time (and without intervention). This also means that interventions that are designed to improve levels of emotional well-being may be unlikely to have a lasting effect. However, much of the research on adaptation to life events has been based on less than ideal designs, and thus strong conclusions can often not be drawn. Recently, psychologists have begun to use large-scale, nationally representative panel studies to examine adaptation to major life events. These studies question some of the results obtained using alternative designs. For instance, analyses of panel data show that although people adapt to marriage and widowhood, they seem to be permanently affected by divorce, unemployment, and the onset of disability. However, many of these results come from a single study from a single nation (the German Socio-Economic Panel Study). Thus, the generalizability of these effects is questionable. In addition, few person-level characteristics have been examined as moderators of these effects. The proposed research will use two additional nationally representative panel studies to examine the full course of adaptation to a broader set of major life events than has been studied in the past. In addition, extending past research, the proposed studies will examine a variety of person-level characteristics that might affect people's reaction and adaptation to major life changes. Four specific aims will be addressed using secondary analysis of existing nationally representative panel data. First, the previous study of Germans showed that people adapted to marriage within about two years. However, the cross-sectional effect of marital status is smaller in Germany than in some other nations. Therefore, to determine whether the effect of marriage depends on culture, analyses of adaptation to marriage will be replicated in two additional nations Australia and Great Britain. Second, prospective panel studies have been used to examine a relatively small number of life events. The two datasets that will be examined in the proposed research include a much broader selection of positive and negative life events. Reaction and adaptation to this broader set of events will be examined. Third, existing studies include few person-level moderators of adaptation effects. Both the British and Australian studies included detailed measures of social support and personality constructs that can be examined as moderators of adaptation effects. Finally, because many life events tend to occur during normative periods of the life span (and because resources that one can use to deal with life events change over the life span) the effects of age on adaptation will be examined. Public Health Relevance: The life course is characterized by normative sequences of major life events that have the potential to significantly impact emotional and physical health. This project will use two very large, nationally representative longitudinal datasets to assess psychological reaction and adaptation to a wide variety of major life events. Investigations into the processes that underlie adaptation will inform theory about life span development, along with efforts to promote recovery from trauma and to improve psychological health.